1. Field of the Invention
This invention relates to well tools, and more particularly to electrical connectors for connecting electrical cables to electrically powered tools even when submerged in electrically conductive liquids.
2. Description of Related Art
For several years, wet connectors have been known for making electrical connections under water or in similar hostile environments in order to supply power to electrically operated devices, or to obtain data gathered by downhole instruments such as transducers for sensing pressures or temperatures. Some such wet connectors are for use in wells, such as oil and gas wells, where conductive liquids, such as salt water or water laden with conductive substances, are usually present.
Applicants are familiar with the following prior U.S. patents which are believed to be pertinent to the invention claimed in the present application for patent. U.S. Pat. Nos. 3,939,705, 4,500,156, 4,583,592, 4,589,717, 4,105,279, 4,510,797, 4,624,309, 4,757,859, 4,442,893, 4,553,428, 4,767,349, 2,620,029, 4,031,969, 4,118,084, 4,266,613, 4,781,607.
U.S. Pat. No. 3,939,705, issued to Bernard J. P. Glotin, et al., on Feb. 24, 1976 and, a division thereof, U.S. Pat. No. 4,105,279 issued to the same inventive entity on August 8, 1978, disclose a side pocket mandrel having a male electrical connector projecting upwardly from the bottom of the offset landing receptacle. This male connector has its lower end projecting through the wall of the mandral where it is connected to an electrical conductor running upward alongside the tubing to the surface. An electrically powered measuring instrument having a wet connector on its lower end and a latch on its upper end is installable in the offset receptacle with its wet commentor engaged with the male connector and its latch engaged in the latch recess at the upper end of the receptacle. The wet connector may contain an insulating fluid such as liquid silicone. The electric cable serves to supply power to the instrument from the surface and to transmit data from the instrument to the surface.
U.S. Pat. No. 4,510,797 which issued to Shelby L. Guidry, et al., on Apr. 16, 1985 teaches use of a full-bore drill stem test tool having one or more recording gauges for storing data gathered by one or more transducers which may sense pressures and temperatures above a downhole valve. The test tool includes a section having electrical contact pins which are located at the upper end of internal longitudinal grooves. Orienting guides are associated with the grooves while an abrupt upwardly facing shoulder is provided a short distance below the grooves. A contact tool lowerable into the well on an electrical cable has means for engaging the abrupt shoulder and when weight is set down, contact arms pivot from a retracted position to a position in which they extend outwardly and upwardly. As this contact tool is subsequently lifted the contact arms are directed by the guides into the grooves. The outer ends of the contact arms travel upward in the grooves and make electrical contact with the downwardly extending contact pins. Thus engaged, data stored in the recording gauges can be transmitted to the surface for read out and the data sensed by the gauges can be displayed at the surface as they are gathered so long as the electric cable remains tensioned sufficient to maintain the electrical connection between the contact arms and the contact pins. Lowering the contact arms only a very short distance will break the electrical continuity. Setting down weight causes the contact arms to be retracted so that the tool can be lifted back to the surface. U.S. Pat. No. 4,553,428 issued to James M. Upchurch on Nov. 19, 1985. This patent discloses use of drill stem test equipment which utilizes the invention of Guidry, et al., U.S. Pat. No. 4,510,797 in such way that pressures below or above the test valve and pressures in the annulus exterior of the test tool are sensed. A contact tool can be run into the well as taught by Guidry, et al. to transmit the recorded data to the surface and/or for transmitting such data as they are sensed, these data in either case being handled by surface readout equipment.
U.S. Pat. No. 4,589,717 which issued to Alain P. Pottier, et al. on May 20, 1986 teaches a wet connector wherein the male connector is lowered into a well and is engaged with a female connector. The female connector contains a dielectric liquid and is meant to operate more than just once. The wet connector has several contact members on each of the male and female portions and is intended for use with a well logging tool.
U.S. Pat. No. 4,624,309 issued to Mark A. Schnatzmeyer on Nov. 25, 1986 and discloses an improvement over the inventions of Glotin, et al. of U.S. Pat. Nos. 3,939,705 and 4,105,279. U.S. Pat. No. 4,624,309 teaches use of a side pocket mandrel having a longitudinal groove extending from the upper end of the offset receptacle to the upper end of the belly of the mandrel. A male connector projecting up from the bottom of the receptacle is engageable with a female wet connector on the lower end of a monitoring tool lowered into the well with an improved kickover tool attached to a slick wireline. The male connector has its lower end extending through the mandrel wall and connected to an electric conductor which extends to surface readout equipment at the surface. The female wet connector initially contains a non-conductive liquid which is displaced upon mating of the connectors in order to flush away and displace conductive substances from the male connector.
U.S. Pat. No. 4,757,859 also issued to Mark A. Schnatzmeyer on Jul. 19, 1988 and is a continuation-in-part of his parent application (Ser. No. 653,585) which matured into his U.S. Pat. No. 4,624,309 just discussed. Additionally, this U.S. Pat. No. 4,757,859 disclosesd an improvement in the female wet connector in that it is provided with reserve capacity for the non-conductive liquid. A floating piston separates the top of the non-conductive liquid from well fluids to which the upper side of the piston is exposed. Thus, although a certain amount of non-conductive liquid is lost upon mating of the connectors, enough non-conductive liquid can be carried for several connection operations.
U.S. Pat. No. 4,442,893 issued on Apr. 17, 1984 to Tommy C. Foust for an improved kickover tool for installing devices in and removing them from side pocket mandrels. The kickover tools disclosed in U.S. Pat. Nos. 4,624,309 and 4,757,859 of Mark A. Schnatzmeyer (supra) are improvements over that disclosed in this earlier patent of Tommy C. Foust. Each of the prior patents cited above is hereby incorporated into this application for all purposes, by reference thereto.
U.S. Pat. No. 4,583,592 issued to Imre I. Gazda on Apr. 22, 1986. This patent teaches use of a zig-zag slot/pin arrangement much like the pin/slot arrangement disclosed in the present application. Gazda's zig-zag slot 354 is shown in FIG. 8 of his patent and the pin 350 is shown to be carried on a floating ring 348 in FIG. 2B. The floating of ring 348 is necessary since the zig-zag slot 354 is formed on lower housing section 206 which, due to substantial preload on compression spring 220, would rotate only with great difficulty because of the great friction which would develop at the ends of the spring and at the o-rings.
U.S. Pat. No. 4,500,156 issued to Khoi B. Nguyen on Feb. 19, 1985. This patent teaches male and female electrical connector members which may be mated downhole in the presence of well fluids, which are expelled from the connector members during mating.
U.S. Pat. No. 4,767,349 issued to Alain P. Pottier, et al. on Aug. 30, 1988. This patent discloses a wet connector very similar to that disclosed in U.S. Pat. No. 4,589,717, by the same inventors and discussed hereinabove on page 5.
U.S. Pat. No. 2,620,029 issued to George F. Turechek, et al. on December 2, 1952 and discloses an electrical connector which can be used to establish electrical contact for initiating a downhole device. One member of the connector is carried on the downhole device such as a perforating gun, the other member may be lowered in a well on an electrical cable, or it may include batteries and be dropped into the well. The members do not latch together.
U.S. Pat. No. 4,031,969 which issued to Roy H. Cullen on Jun. 28, 1977 discloses an electrical connector for latching an electrical cable to a downhole electric motor to furnish electrical power thereto for rotating a drill bit for forming the borehole.
U.S. Pat. No. 4,188,084 issued to Georges Buresi, et al. on Feb. 12, 1980. This patent discloses an electrical connector having two members, each carrying electrical contacts, which can be mated downhole to place their corresponding contacts in engagement with one another. The connection can be made while submerged in water, or the like fluids.
U.S. Pat. No. 4,266,613 issued to Gene T. Boop on May 12, 1981. This patent discloses an arming and disarming device for use with explosive devices downhole in wells, the disarming device becoming armed responsive to hydrostatic pressure in the well fluids in one embodiment, or as a result of grease pressure injected into the arming mechanism of a second embodiment.
U.S. Pat. No. 4,781,607 which issued to William D. Rumbaugh on Nov. 1, 1988 discloses a wet connector for connecting a wireline retrievable pilot valve to an electrical conductor as the pilot valve is installed in its receptacle, located at a downhole location in a well. The electrically powered pilot valve controls a surface controlled downhole safety valve located not far from the pilot valve and preferably located a short distance below it. The pilot valve is carried on a locking device which locks into the offset receptacle of a side pocket receptacle which forms a part of the well tubing.
WORLD OIL Composite Catalog of Oil Field Equipment and Services, 1982-83 Edition, pages 3180-3187, shows certain well testing equipment and services provided by Flopetrol (a member of the Schlumberger Group). Illustrated are SPRO (Surface Pressure Readout) equipment and a latching wet connector, but details of its construction are not shown. In addition, the 1986-87 edition of WORLD OIL Composite Catalog, pages 2054-2060 mentions (at page 2058, lefthand column near top) an SPRO system which appears to include a "wet connect," however, no structure for such wet connector is disclosed. Similar material is published in WORLD OIL Composite Catalog, 1988-89 Edition, pages 3340-6-3340-11. An SPRO is mentioned at page 3340-7, but no structure is disclosed. At page 3340-8 "SPRO" and "wet connect" are mentioned in the same manner seen at page 2058 in the 1986-87 Edition, mentioned above. Again, no structure is disclosed. At page 3340-8 of the 1988-89 catalog, mentioned above, in the lefthand column, lower portion, there is mentioned the ". . . capability of reprogramming the downhole electronics." How such reprogramming is to be accomplished is not revealed.
There was not found in the known art a wet connector for releasably locking the lower end of an electrical cable to a remote electrically powered device for transmitting electrical power or signals therebetween.
The present invention is an improvement over the known wet connectors for running on an electric cable in that it enables mating of male and female connectors in a hostile environment, such as downhole in a well which may contain salt water and/or other conductive substances, and also to latch them together to permit tensioning of the electric cable and yet are readily releasable for ready withdrawal to the surface. The present invention is also directed to systems utilizing wet connectors for connecting an electric cable to remotely located electrically operated tools, such as downhole well tools, and wherein such wet connectors are releasably latched or locked in place.